Ibn Isḥaq was born in al-Medina in 85 AH (704) and died in Baghdad around 150–159 AH (761–770).
Ibn Isḥaq collected oral narrations about the life of the Prophet Muhammad. These narrations, which he orally dictated to his pupils, are now known collectively as Sīratu Rasūlillāh (Arabic: سيرة رسول الله "The Life of the Messenger of God").
Ibn Hisham - An edited copy, or recension, of Ibn Isḥaq's work by his student al-Bakka'i, which was further edited by Ibn Hisham. Al-Bakka'i's work has perished and only Ibn Hisham's has survived, in copies.
WARNING: There are some things written in this book which have no source while other things written are based on weak sources (i.e. weak Hadiths). Sometimes the book provides sources, and other times it doesn't provide sources.
Alfred Guillaume's 1955 English translation of Ibn Isḥaq is currently favored by non-Arabic speakers, although some have questioned the reliability of this translation. In it Guillaume combined ibn Hisham and those materials in al-Tabari cited as ibn Isḥaq's whenever they differed from or added to ibn Hisham, believing that in so doing he was restoring a lost work. The extracts from al-Tabari are clearly marked, although sometimes it is difficult to distinguish them from the main text (only a capital "T" is used).